Problem: $9bc + 2bd + 10b - 7 = -9c + 10$ Solve for $b$.
Explanation: Combine constant terms on the right. $9bc + 2bd + 10b - {7} = -9c + {10}$ $9bc + 2bd + 10b = -9c + {17}$ Notice that all the terms on the left-hand side of the equation have $b$ in them. $9{b}c + 2{b}d + 10{b} = -9c + 17$ Factor out the $b$ ${b} \cdot \left( 9c + 2d + 10 \right) = -9c + 17$ Isolate the $b$ $b \cdot \left( {9c + 2d + 10} \right) = -9c + 17$ $b = \dfrac{ -9c + 17 }{ {9c + 2d + 10} }$